Laser apparatus and method of driving diffraction grating

Abstract

A laser apparatus is disclosed. The laser apparatus has a diffraction grating that receives laser light from a semiconductor laser, emits first order diffracted light having a predetermined wavelength to the semiconductor laser, and reflects zero-th order light, a reflection section that reflects the zero-th order light reflected by the diffraction grating, a hold section that holds the diffraction grating and the reflection section while an open angle of the diffraction grating and the reflection section is kept constant, the hold section being rotatable with a fulcrum of an intersection of an extended line of a front surface of the diffraction grating and an extended line of a front surface of the reflection section, and a linear drive section that rotates the hold section with a linear motion of a piezoelectric device that expands and shrinks by the piezoelectric effect.

1. A laser apparatus, comprising:
 a diffraction grating that receives laser light from a semiconductor laser, emits first order diffracted light having a predetermined wavelength to the semiconductor laser, and reflects zero-th order light; 
 reflection means for reflecting the zero-th order light reflected by the diffraction grating; 
 hold means for holding the diffraction grating and the reflection means while an open angle of the diffraction grating and the reflection means is kept constant, the hold means being rotatable with a fulcrum of an intersection of an extended line of a front surface of the diffraction grating and an extended line of a front surface of the reflection means; 
 linear drive means for rotating the hold means with a linear motion of a piezoelectric device that expands and shrinks by the piezoelectric effect; and 
 a connection portion that fits a sphere member that protrudes from the hold means and a reception portion disposed on a moving member that performs the linear motion of the linear drive means. 
 
   
   
     2. A drive method of varying an angle of a diffraction grating of a laser apparatus having a diffraction grating that receives laser light from a semiconductor laser, emits first order diffracted light having a predetermined wavelength to the semiconductor laser, and reflects zero-th order light, reflection means for reflecting the zero-th order light reflected by the diffraction grating, hold means for holding the diffraction grating and the reflection means while an open angle of the diffraction grating and the reflection means is kept constant, the hold means being rotatable with a fulcrum of an intersection of an extended line of a front surface of the diffraction grating and an extended line of a front surface of the reflection means, and linear drive means for rotating the hold means with a linear motion of a piezoelectric device that expands and shrinks by the piezoelectric effect, the drive method comprising the steps of:
 determining whether the wavelength detected by the detection means matches a designated wavelength; 
 stopping the linear drive means when the determined result at the determination step denotes that the detected wavelength matches the designated wavelength; and 
 driving the linear drive means so that the detected wavelength becomes close to the designated wavelength when the determined result at the determination step denotes that the detected wavelength does not match the designated wavelength.